CODEWITHSUNDEEP
sqlsql-serversql-tuning
Naxi
Naxi

Reputation: 2026

combining multiple UNION inside a view in sql server

I want to create a view as below.

Create view SomeView
AS
SELECT DISTINCT ISNULL(ID,'ID') as Id, 
ISNULL(ID,'unknown') + ':' + 'ID' AS label,
ISNULL(ID,'unknown') AS [value]
FROM [test].[emp].[OrgView]
  UNION
SELECT DISTINCT ISNULL(EMP_ID,'ID') as Id, 
ISNULL(EMP_ID,'unknown') + ':' + 'EMP_ID' AS label,
ISNULL(EMP_ID,'unknown') AS [value]
FROM [test].[emp].[OrgView]
  UNION
SELECT DISTINCT ISNULL(LICENSE_NO,'LICENSE_NO') as Id, 
ISNULL(LICENSE_NO,'unknown') + ':' + 'LICENSE_NO' AS label,
ISNULL(LICENSE_NO,'unknown') AS [value]
FROM [test].[emp].[OrgView]
.
.
.
.
.
10 such selects

So in this case, will a call be made for each select block or it will just one call ? I do not want this to make 10 different calls for each select. Please point me to some resource online if you know.

Upvotes: 0

Views: 32

Answers (1)

Gordon Linoff
Gordon Linoff

Reputation: 1270011

Unpivot using APPLY:

SELECT DISTINCT COALESCE(v.ID, v.id_default) as Id, 
       COALESCE(o.FIRST_NAME, 'unknown') + ':' + v.name_suffix AS label,
       COALESCE(o.VALUE, 'unknown') AS [value]
FROM [test].[emp].[OrgView] o CROSS APPLY
     (VALUES (o.ID, 'ID', 'Unknown'),
             (o.EMP_ID, 'ID', 'EMP'),
             (o.LICENSE, 'LICENSE_NO', 'LICENSE_NO'), . . . 
     ) v(ID, id_default, name_suffix);

Upvotes: 1

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